Trying to get it all straight

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judson   10 mW

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Trying to get it all straight

Post by judson » Jun 30 2015 3:06am

I hope this comes out alright, can't sleep so I am gnawing away at my electric bike dream deep into the night. I posted recently about my vision and asked about the frame I am acquiring for the purpose. Long story short, I think I am going to pick up an old mountain bike ('91 Rockhopper) to build into an ebike for commuting use. The commute is 10 miles through the heart of Seattle, three hills in the way (two long and low, the other is short and punchy). I am of average size and can charge at work and home. I am looking to pedal assist not full electric there and back.

Until recently I was thinking of a rear DD, for ease of use, reliability and cost. Now I am switching camps to mid drive, likely the BBS02. My reasons are that I like to tinker, it seems better for the aforementioned hills and I can keep the weight low and centered.

Here are a series of questions that I thought about making into different posts each but for reasons of efficiency I am just going to go for it.

1) I have heard that mid drives can be hard on knees because of spacing changes made to the crank arms in order to accommodate the motor width. Is there any truth to this? I have bad knees.

2) I know a little about electricity having done the majority of wiring on my own house. I also help the students at my school build robots and so I understand the general concept of motors and controllers but I have trouble seeing the whole picture with respect to the electric bike. Is there a primer somewhere that helps with amps and watts etc as well as wiring digrams perhaps explaining the core elements in any ebike. I tried the wiki page http://www.endless-sphere.com/w/index.p ... nners_info and while at first it seemed to be going in the right direction it quickly got WAY too technical too fast.

3) I am concerned about switching gears with a mid drive system. Seems like I am just going to mash the gears to shreds shifting while the motor is churning away. What are people doing about this? Do I necessarily need to get a internally geared rear hub, or even perhaps a Nuvinci (pricey!!) :shock:

4) Final question I promise. With the BBS02 I am restricted to one chainring (correct?), that means the only gears I have access to are the 9 rear cogs. Is this not a problem? My commute has a lot of flat where I would like to be clicking along at 20mph (perhaps 25?), but there is also that one doozy of a hill.

Okay, that was WAY to long but I don't have the heart to erase it either. Take pity on me! :(

Please let me know if I am off my rocker or have omitted some super important detail. Thanks everyone!!
Cargo Bike: eZee rear hub, 25A controller, 48V 11.6Ah LiMn battery, TDCM BB torque sensor atttached to Cycle Analyst v3

Daily Driver: BBS02 750W mid-drive, 48V 13.5Ah battery

markz   100 GW

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Re: Trying to get it all straight

Post by markz » Jun 30 2015 3:44am

I am up too, and its 2:33am MST here, but I am just about done my daily routine and will get a big glass of chocolate milk and down it like booze right before bed.

Yes, I read that too, people do have problems with the knees on the BB system. Its a pricey ordeal to go with that right off the top. I wouldnt do it.
I would stick with the originial DD, the 1500W leaf would do you amazingly well I believe. Depending on the hills and all.
Either that or the MAC from em3ev another reputable source for ebike parts. You can buy a kit from him too, even batteries. Smart choice on that.
I would recommend the MAC for sure *I couldnt find the thumbs up emicon* You need to talk to people to find out what tooth count would be good.
**Thumbs Up**

Bro, you got a huge learning curve ahead of you.
I took electronics in college, I am an Electronics Technician by trade, Telecommunications Diploma, worked for Nortel. And I am still learning. But I admit I am a slooow learner. A primer course, would be wikipedia for sure. The battery section has a good thread on charging and lipos and such. I believe there was a member that pointed you towards a beginners guide in your other thread as a starter.

Heck even sometimes I have to stop and say, "Self, does VxA=Ah? no no its Watts. But how do I get Wh? VxAh, then theres the windings, phase amps, phase wires, hall wires and what do they do. Then you got this that and the other.

I will tell you this. Do Not Buy RC Lipo, buy a package deal from EM3EV that comes with a charger. Get some very common voltage, 48V, then go for 15Ah or 20Ah battery package. Ah is like your gas tank the more, the further you go.

You can also look at YesComUsa.com, Leafmotor.com, Leafbike.com, ebikes.ca in Vancouver top notch company, sffbike or something is good
Stay away from BMS Battery.

Stick to something simple, BB systems seems complicated to me.

Good Night!

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dogman dan   100 GW

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Re: Trying to get it all straight

Post by dogman dan » Jun 30 2015 6:15am

Nothing complicated about what you want to do. Just about any kit with a medium size power controller will do the job you want. By medium, I mean anything in the 500-1000w range. 20-25 amps controller is plenty.

A DD motor will be heavy, and I see nothing that indicates you need to go that route. A rear geared motor will be lighter, and a bit perkier and more efficient when riding stop and go in a city. So Mac, BMC, E-bikekit, or the Ezee will get er done nicely.

Since you live very close, check out Grin technology for the Ezee.

Typically these kits will run at 500-800w if you use 36v, and 900-1200w when you run 48v. 48v will be faster, which is nice when you need to get going to stay safe. But 36v will get you 20 mph, and be enough to get your hills done with not too heavy pedaling.

As for the bottom bracket motor, I don't have experience with the bbso2 myself. But I can say a few things,

1--- The 9 gears in back will be plenty. You are all done with the little chain rings if you have any kind of motor. You won't need them, and you will be climbing very steep hills at 15 mph now. No more crawling at 5 mph, period.

2---- You do need to ease off the throttle when shifting. It will be hard on chains to change gears when feeding the chain 800w. IGH, could be a problem too, if you don't blip the throttle when you shift.

3 --- The knees. I'm not sure how much wider the pedals are on a BBs02 setup. They will be wider than a road bike, but that applies to any mountain bike anyway. I think if it's going to bother your knees that much, you simply don't pedal so hard. I don't know what your problem is, but if your cartilage is gone, I would think your knees won't like pedaling anything much. Not pedaling at all is a definite option with the BBso2. Definitely, either way, get a throttle controlled kit if you need to rest the knees on part of the ride. So you don't have to pedal to make it go.

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arkmundi   1 GW

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Re: Trying to get it all straight

Post by arkmundi » Jun 30 2015 8:47am

markz wrote:I would stick with the originial DD, the 1500W leaf would do you amazingly well I believe. Depending on the hills and all. Either that or the MAC from em3ev another reputable source for ebike parts. You can buy a kit from him too, even batteries. Smart choice on that.
I'd second the choice of either the Leaf or MAC, my two favourites for affordable & powerful. See my Top 10 eBike Conversion Kits & Where to Buy thread for more choices. I believe powering an eBike in the 1500 to 2000 watt range to be the sweet spot for most people. Both those motors will handle upwards to 2000 watts just fine. Rear hub motors, where in my mind is the best place for the DIY'er with a kit and their MTB. For ease & peace of mind, the KISS approach.
markz wrote:I will tell you this. Do Not Buy RC Lipo, buy a package deal from EM3EV that comes with a charger. Get some very common voltage, 48V, then go for 15Ah or 20Ah battery package. Ah is like your gas tank the more, the further you go.
Again, some really good advice for those adventurous newbies looking for long-term reliability. More than motor, the battery and how you charge it up, should take up your time doing the research. I advise going with automotive EV class battery tech. RC lipo needs to be light, for a good reason. But doing so at a loss to safety. Stick with LiFePO4 - see Buyin a battery pack for more options.

One last: I believe the Specialized Rockhopper may be aluminium. I'd recommend you reconsider that in favour of a steel frame MTB. See Letters to my nephew where I advise that and elaborate on a few choices.

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Drunkskunk   100 GW

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Re: Trying to get it all straight

Post by Drunkskunk » Jun 30 2015 11:51am

the decision between Direct drive hubs, geared drive hubs, through the chain drives, and even friction drives can leave you pulling out your hair. There is no "best". There is, however, a "worst". But all of them work well, so in most cases, it's just a matter of personal choice.

1) Yes. No. Maybe. Some people's knees will go into revolt if their feet are 1 inch further apart. Most people's won't. Bikes come in a wide variety of pedal spacing, and the BBS0X series pedal spacing isn't that different from what you would find on a Fatbike. If the problem was wide spread, Bafang,and every fatbike manufacturer would have been sued out of business by now for selling knee destroying wide spaced pedal bikes. You might have a problem, but it's extremely unlikely. You might get sore knees just because your body isn't used to exercising in a new position. You might also get sore feet in new shoes. Pretty much a non-issue.

2) I think we tend to forget that not everyone who comes here has Ohm's law tattooed across their chest. The Ebikes for beginners section of our wiki probably scares off more people than it helps. Unfortunately, the gulf of knowledge between the true beginner to what gets discussed here is wide and deep. And for that reason, there isn't an easy generic way to bring people up to speed. It's an individual journey. So ask lots of questions.

3)With a mid drive you need to back off the throttle when changing gears. Don't shift at full torque. it's the same as shifting gears on a motorbike. you don't keep the throttle wide open when shifting, or you'll trash the gears. An internal geared hub would suffer the same troubles. A Nuvinci isn't geared, so it can be shifted under load, but they also suffer from a 10% efficiency loss.
Keep in mind that the gears and chain on your bike are considered wear parts. they will eventually wear out no matter what you do. And they are designed for normal human power, around 100 to 150 watts. Add a 750 watt motor to them, and they will wear out faster.
Sometimes it's hard to make the mental transition to accept that these parts are going to wear out, and you will be replacing them, and that it's perfectly ok to be abusing them.

4) you're not going to shifting nearly as much as you think. The second bike I built, I accidentaly screwed up the derailleur cable when I assembled the bike, and didn't catch the mistake for a year. The bike couldn't be shifted, but for that entire year, I hadn't had a need to shift gears, so I never caught the mistake.
Buy the ticket, take the ride.
Monster Bike:http://endless-sphere.com/forums/viewto ... =6&t=38667

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beast775   100 kW

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Re: Trying to get it all straight

Post by beast775 » Jun 30 2015 12:01pm

Being your first ebike, it will be exactly that,then once you get it running you will want to upgrade soon,so dont sweat it,but get a good kit and reap the benefits.lots of friends riding macs here and they work great,were similar topography.
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I spent all my money on bicycles women and beer the rest i just wasted.

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Ykick   100 GW

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Re: Trying to get it all straight

Post by Ykick » Jun 30 2015 12:59pm

2kW eBikes and above are really mini-motorcycles IMO along with that of many governing bodies. By nature of the motor and battery required it can add enough weight that any resemblance to a “pedal” bicycle goes out the window. They’re sure fun and often my choice for general day to day riding, commuting, etc. But remember they’re basically an illegal motorcycle if/when ridden on the street in many countries.

OTOH - 500-900W using something like small geared hub 4lb Q100/128 series motors = much more “reasonable” type eBike. Especially for people who already pedal. Keep the battery under 5-6lbs and the entire added weight is only a little over 10lbs. Not bad if you start with a relatively lightweight 25-30lbs bicycle.

The real Hat trick (and place to focus as much of your prep work) is the battery. I’ve been at this for a long while and still unable to get what I really want/need. I keep hearing praise for can packs supposedly lighter, safer and capable of high rate discharge but I’ve yet to find the order page like I can typing in Hobby Lipo. But that’s just that - hobby cells….

‘Got nothing about BB drives other than I want one. They’re an attractive way to bypass wheel building tutorials but a different animal that I’ve never yet had the pleasure to experience.

Plan to build more than one is all the wisdom I have left to offer. That way you’ll better understand the ranges available and may help keep it fun for the entire family and circle of friends. Welcome to the madness!!!
Talent must not be wasted.... Those who have talent must hug it, embrace it, nurture it and share it lest it be taken away from you as fast as it was loaned to you.

- Frank Sinatra

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neptronix   100 GW

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Re: Trying to get it all straight

Post by neptronix » Jun 30 2015 1:06pm

judson wrote:1) I have heard that mid drives can be hard on knees because of spacing changes made to the crank arms in order to accommodate the motor width. Is there any truth to this? I have bad knees.
I also have very, very bad knees. They knock, they pop, they grind, they hurt.
On my BBS02, one pedal stuck out about 10mm more than the other. I was able to correct this down to 3mm extra distance by machining a set of cranks. But, the pedals overall came out too wide and pedaling was always iffy for me. It was the main reason i went back to trusty ol' hubs - so i could have the usual narrow pedal spacing that most bikes have. Dramatically less painful.

The other thing about the BBS02 is that the pedal cadence was a bit too low for me, but i was using a 12S battery instead of a 13S battery. That may have been a contributing factor for me. The lower power of the BBS02 meant that i had to put in a hell of a lot of pedal power to keep my top speed ( 30mph ) up, or get to it, and i didn't like that.
judson wrote:2) I know a little about electricity having done the majority of wiring on my own house. I also help the students at my school build robots and so I understand the general concept of motors and controllers but I have trouble seeing the whole picture with respect to the electric bike. Is there a primer somewhere that helps with amps and watts etc as well as wiring digrams perhaps explaining the core elements in any ebike. I tried the wiki page http://www.endless-sphere.com/w/index.p ... nners_info and while at first it seemed to be going in the right direction it quickly got WAY too technical too fast.
Good, you've got a head start. A multimeter will tell you a lot of what you need to know. But, kits usually come prewired correctly, so there isn't a lot to mess with. Most hub motors come with standard phase/hall coloring and positioning as well. Connectors are usually standardized on Chinese stuff. It's north american supplied kits that typically change all the connectors and pin locations, and that becomes a pain in the butt..
judson wrote:3) I am concerned about switching gears with a mid drive system. Seems like I am just going to mash the gears to shreds shifting while the motor is churning away. What are people doing about this? Do I necessarily need to get a internally geared rear hub, or even perhaps a Nuvinci (pricey!!) :shock:
I had that problem with my BBS02 until i disabled pedal assist and used throttle only. But i would get impatient between shifts because there were delays in engaging/disengaging the power, and much 'wailing and gnashing' of the gears would result. It's another reason why i don't like mid drives.
judson wrote:4) Final question I promise. With the BBS02 I am restricted to one chainring (correct?), that means the only gears I have access to are the 9 rear cogs. Is this not a problem? My commute has a lot of flat where I would like to be clicking along at 20mph (perhaps 25?), but there is also that one doozy of a hill.
That's not a problem. Just get the right gearing for the job. The electric power will boost you a lot and gear that normally stalls you up a hill while pedaling will suddenly become very useable. Some of us big power hub motor guys only use a single gear, or a 7 speed cluster where only 2-3 gears are actually used, because the motor is doing 75-99% of the pedaling for you :mrgreen:
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: 20" eZee on a Cannondale Semi Recumbent.
Whipper-snapper: ? on a lightweight BikeE Semi Recumbent

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judson   10 mW

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Re: Trying to get it all straight

Post by judson » Jun 30 2015 1:39pm

Thanks everyone for all the helpful thoughts. I am definitely hearing the thoughts about going back to a DD rear hub motor or even a geared rear hub. Let me push back for a second (then I can roll over later with honor).

One of the reasons that I was looking towards the mid drive was that in the future if this goes well I was hoping to construct a child carrying platform with handle bars off the seat post. It just seems like, especially in the wattage some of you were mentioning (did I see 2000W? :shock: ) I am putting a lot of weight on the rear axel already. Then add to that my over-engineered child platform plus a 40 pound child. Maybe I am dreaming regarding the child mover, but it seems more attainable with the motor centered between the two wheels (as well as the battery, but that could be done with either motor type right?).

Cue the noob question, what makes a mid drive so difficult? I scouted out this http://em3ev.com/store/index.php?route= ... uct_id=166 kit that comes with controller break cut outs etc. Still need to research a battery and obviously do the installing. But it looks fairly straight forward. And if it is not could I pay an ebike shop to do it?

Thanks!
Cargo Bike: eZee rear hub, 25A controller, 48V 11.6Ah LiMn battery, TDCM BB torque sensor atttached to Cycle Analyst v3

Daily Driver: BBS02 750W mid-drive, 48V 13.5Ah battery

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neptronix   100 GW

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Re: Trying to get it all straight

Post by neptronix » Jun 30 2015 1:50pm

A mid drive is not difficult to install, probably the easiest. A BBS02 will come all wired up correctly.
I dunno if you have a local ebike shop that can install a kit for you. You're probably going to need to purchase some tools and DIY.

Hub motor rear weight is no big deal unless you're offroading or have a full suspension bike ( it becomes unsprung weight and that dampens the rear shock's ability to do it's job ) - it also gives you a more solid wheel to hook rear cargo up to. A MAC is just a few pounds heavier than a BBS02, so if you really wanna weight-weenie, a 10T MAC on 36-48v would do ya just fine. I ran a 8T MAC for a very long time, even when i was way heavier than i am now ( was 270lbs ) and it pushed me around and up hills very well, though it did build a lot of heat on >7% grades that are a mile or longer. A 10T has more torque than an 8T, so it should do.

I do use a 1500W leafbike motor at 4000W right now, and it flies up 7-10% grades at 30-40mph. Direct drive is more durable at high power than geared, any day.. but if you only want to do 20-25mph, a big geared motor will the job for sure up hills and whatnot.
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: 20" eZee on a Cannondale Semi Recumbent.
Whipper-snapper: ? on a lightweight BikeE Semi Recumbent

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arkmundi   1 GW

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Re: Trying to get it all straight

Post by arkmundi » Jun 30 2015 1:59pm

neptronix wrote:I ran a 8T MAC for a very long time, even when i was way heavier than i am now ( was 270lbs ) and it pushed me around and up hills very well, though it did build a lot of heat on >7% grades that are a mile or longer. A 10T has more torque than an 8T, so it should do.

I do use a 1500W leafbike motor at 4000W right now, and it flies up 7-10% grades at 30-40mph. Direct drive is more durable at high power than geared, any day.. but if you only want to do 20-25mph, a big geared motor will the job for sure up hills and whatnot.
Then you're the person to ask, that, running at 2000 watts, would you in general recommend a MAC 8T or 10T, or a a comparable 1500 nominal watt Leaf motor? Understanding the MAC is geared and the Leaf is a DD. And typical riding, with loaded weight and hills?

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neptronix   100 GW

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Re: Trying to get it all straight

Post by neptronix » Jun 30 2015 2:31pm

I would not recommend running a MAC at anything more than 1500W continuous for short periods of time based on my experience.

If you want to simulate the performance of the MAC 10T, select the BMC_V2 TRQ model in the ebikes.ca sim and simulate away.

http://www.ebikes.ca/tools/simulator.html

The leafmotor 1500w doesn't really have an equivalent in the motor simulator, but my thread on the motor can tell you a decent amount about it's performance in the real world.
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: 20" eZee on a Cannondale Semi Recumbent.
Whipper-snapper: ? on a lightweight BikeE Semi Recumbent

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